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  1. #1

    Unhappy No P0128 Code Threads?

    Just joined this forum. Before joining, I searched for P0128 error code as read by Auto Zone Tech. (The Check Engine light is on) No hits!? Thought maybe because I needed to join. Did so. Tried same search in every related forum. Still, No hits!
    Has nobody ever gotten a P0128 code? the web says it's a thermostat. Any feedback?

    Thanks for your reples in advance.
    2005 Chevy TrailBlazer
    Monroe, Georgia

  2. #2
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    dwill3015's Avatar
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    Welcome to the site! All I can come up with is this...

    ECT Less than thermostat Regulating temperature.
    Last edited by dwill3015; 09-24-2008 at 09:44 PM.
    Darcy
    Washington State
    2006 Silverado 2500HD LT3 4X4 CC SB Duramax LBZ
    Tuff Country 6" lift, 35" Toyo M/T's on 20" Ultra Peacemaker wheels, Quadzilla Stealth2 programmer, Diamond Eye 5" cat-back exhaust, factory Special order color Yellow.

  3. #3

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    Quote Originally Posted by dwill3015 View Post
    Welcome to the site! All I can come up with is this...

    ECT Less thank thermostat Regulating temperature.
    Appreciate the feedback. Hopefully others will have additional info. I am pretty good at electromechanical repairs and am hoping it is a sensor or a simple thermostat replacement. I do not want to pay a dealer to find the problem and fix it. It is expensive and usually a well padded repair bill. I will stay tuned.

  4. #4
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    dwill3015's Avatar
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    I'm glad you can understand the definition. Good luck with it and let us know your progress.

  5. #5
    Jr. Apprentice
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    MY p0 128 CODE SHOWED UP, THE BOOK THAT WAS WITH SCANNER SAID WATER TEMPERATURE SENSOR WAS NOT WORKING PROPERLY
    aNY ONE KNOW WHERE THE WATER TEMP SENDING UNIT IS ON A 4.3 v-6 IN 2003 SILVERADO 4X4? Thx, Bill

    ---------- Post added at 02:05 PM ---------- Previous post was at 02:01 PM ----------

    I just used scanner for my check engine light same code Po128 says water temperature sensor that sends info to gauge. They used to be a brass sensor that screwed into intake manifold where water ran past with a single wire they used to be cheap, like $5.00 or so. I don't know where it is on V-6 Silverado engine if you find out get back to me eh? thx, Bill

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    I'm not sure where it is located but I pasted below a thread that should connect you with a Chiltons. Recently, someone was having some problems linking into it, so hopefully it will work for you. If you try, let us know if one of the ways mentioned on the tread works.

    http://www.gmtruckclub.com/forum/sho...lton-site-link


    Mike (Denver, CO) - 2008 Sierra 1500 Z71 SLE 5.3L 4WD

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  7. #7
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    If you do have this problem the first thing you want to do is replace the Thermostat.. If that doesnt fix it then do the sensor.
    Mike

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  8. #8

    Default

    Here's what I'd probably do:

    1) Get your scanner out (assuming you have one. If you don't, the ECT is a simple thermistor and could be tested with a voltmeter, the idea is basically the same). By scanner I mean something more than a code reader -- something that can read sensor data.

    2) Look at the stored freeze frame data. See what the ECT reading actually was.

    3) Look at the real time PID's and see what the ECT is reading on a cold engine. If the ECT is not reading something close to the actual underhood temperature, then I would begin to suspect the ECT is at fault.

    4) If the ECT is reading something believable, run the engine and let it warm up (if it will). If the engine warms up some, but not all the way, then I would begin to suspect the thermostat is stuck open.
    Last edited by MrShorty; 12-15-2010 at 09:16 PM.
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  9. #9
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    I just had this problem with my car, and it was the T-stat it was running 10 degrees cooler than the T-stat was supposed to allow.. And the T-stat wasnt sticking and even tested good after i replaced it..

  10. #10

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    Its the thermstat front left corner of engine
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